Why notice that the density of Si divided by the density of HA is about 3/4 and write!
!
And then use that with!
!
When it means we have to solve the sextic!
!
When we could have just noticed !
!
And then merely have to solve the quadratic!
!
The reason is that by first looking at the ratios of our densities instead of their differences we
have bone as part of the Ancient Greek elements and that takes us to archaeology. What is
Archaeology but the study of the decomposition of bone in its exposure to earth, air, and
water?!
I found it interesting that bone was appearing in the context of Earth, Air, and Water. I knew
that the oldest skeletons of humans and their ancient ancestors were unearthed in Africa, and
that Chinese archaeologists wanted to find skeletons in China just as old so they could show
they arose independently of any other people. The argument as to why they had not found
anything as old as in Africa was that Africa is drier so skeletons preserve longer. And, this
brings me to my point:!
The organic component of bone is collagen and decomposes early on. What is left is the
mineral component (hydroxylapatite, HA). The amount of bone in eight weeks that decays in
soil (Earth) is the same as the amount of bone that decays in air in two weeks (CAP, 1986) and
the primary factors in bone decomposition are soil, air, and water. Mendelian genetics are are
at the core of biological evolution and the study of that is the study of bone decomposition. I
need only present now, my earlier work. The mineral component (HA) decomposes in exposure
to water into calcium and phosphates.!
Thus in humid conditions bones can decompose in decades and in dry conditions can be
preserved for thousands of years. Francesco Berna, Alan Mathews, and Stephen Weiner report
(2004):!
We measured the ionic activity products at “steady-state” conditions and we identify a
recrystallization window between pH 7.6 and 8.1, which defines the conditions under which
bone crystals dissolve and reprecipitate as a more insoluble form of carbonated hydroxyl
apatite. As these conditions are common in nature, most fossil bones will not maintain their
original crystals with time.!